Implanted medical devices or biomaterials can present microenvironments that are conducive to bacterial colonization or infection. Such infections can require repetitive hospital visits or can even require removal or replacement of the implanted device or material. For example, approximately 1 million inguinal and 20,000 ventral herniorrhaphies are performed yearly in the United States. It is estimated that approximately 3 to 8 percent of patients who undergo such surgery develop post-operative infections. These types of infections can cause complications that require longer post-surgery care and escalate health care costs. It has been estimated that surgical site infections have increased hospital stays by approximately 7 days with costs increasing from $3,000 to $30,000. Overall surgical implant infections costs have been credited with increasing direct medical costs by more than $3 billion annually in the US. In addition to the financial burden caused by repetitive implant surgery and longer inpatient hospital stays, infections can be fatal or near fatal to a significant portion of patients.
At least some degree of bacterial entry into a surgical site is nearly unavoidable at the time of surgery. Bacteria can be introduced in surgeries that include the implantation of medical devices and materials as well as surgeries that do not. However, the presence of an implant can complicate the clearance of bacteria from the surgical site. Bacteria introduced at the time of implantation can contact the implant, bind to and colonize the implant surface. If bacterial colonization occurs on the surface of the implant, traditional means of treatment including the use of systemic antibiotics, are largely unsuccessful in treating the infection. Because of the difficulty of clearing bacteria that have populated the implant surface, it is common for surgeons to completely remove the implant, place patients on long term systemic antibiotics to clear the infection, and re-implant the medical device.
Currently available procedures for treating infections typically involve administration of antibiotics. Others such as Gristina et al. (U.S. Pat. No. 5,292,513) disclose methods for nonspecific cellular immune stimulation. Ziegler et al. (U.S. Pat. No. 7,906,132) disclose anti-infectious, biocompatible titanium coating for implants, and methods for the production thereof. O'Hagan et al. U.S. Pat. No. 7,597,908 discloses use of micro-particles with adsorbed antigen to stimulate immune responses towards the specific antigen at a systemic level.